Asymmetric feeding active leaky-wave antenna arrays

Abstract

The active leaky‐wave antenna arrays have been demonstrated, which integrate several microstrip leaky‐wave antenna elements with a single HEMT oscillator as an active source at 10.2 GHz. To excite the first higher order mode, the leaky‐wave antenna is fed asymmetrically. The reflected wave due to the open end of each leaky‐wave antenna element has been suppressed by the symmetric configuration of this antenna array. When comparing with the measured radiation pattern of the single‐element antenna, we found that 1×2 and 1×4 antenna arrays can effectively suppress the reflected power by more than 5.5 and 10.5 dB, respectively. Furthermore, the power gains are more than 2 and 3.16 dB higher than the single‐element antenna with a measured EIRP of 18.67 dBm. © 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 18: 14–17, 1998.

Microstrip leaky‐wave antenna with beam‐patterns switchable capability

“…When the operating frequency increases, a pencil beam scans toward to the end-firing direction (z direction) in H-plane (y-z plane), and a fan beam radiates in quasi-E-plane. The pointing angle of pencil beam is determined as: ϭ 90°Ϫ arcsin (␤ z /k 0 ), where ␤ z is the phase constant of complex propagation constant k z ϭ ␤ z Ϫ j␣ z , k 0 is the wave number of free space wave [2,3]. To excite the first higher order mode in the operating region of frequency, the MLWA element should be fed asymmetrically.…”

“…Microstrip leakywave antenna (MLWA) has the advantage of simple construction, low-profiles, narrow beam width, and frequency-scanning ability. MLWA has been applied in many fields, such as cruise control and radiolocation, in the last few years [3][4][5].…”

“…It's a single-beam antenna. The single-beam MLWA has been widely theoretically studied and experimentally applied since then [2,3]. There are some researches focusing on the dual-beam MLWA [4,5].…”

Active asymmetrically feeding dual-beam leaky-wave antenna

“…Some research of the leaky-wave antenna have also been intensively investigated in [ 11- [2]. Here, an active phase-shifterless dual-beam scanning antenna (see Fig.…”

“…Another advantage of this design is no reflected wave due to the unmatched load of the open end of the leaky-wave in finite-length situation. Although the reflected wave can be suppressed by the array topology [2] or the longer length[l], this balanced matched load of two ports design can be thought as a matched load on both sides of the open end in this circuit; thus, this two-port design can suppress the reflected wave.…”